Process for preparing therapeutically active substances



Patented Apr. 24, 1945 PROCESS F OR PREPARING THERAPEU- TICALLY ACTIVE SUBSTANCES Randolph T. Majon'Mountainside, and Howard T. Bonnett, Westfield, N. J assignors to Merck & (30., Inc., Rahway, N. J a corporation of New Jersey No Drawing. Original application January 30,

1940, Serial No. 316,404. Divided and this application May 22, 1943, Serial N 0. 488,058

3 Claims.

This application is a division of our co-pending application Serial No. 316,404, filed January 30, 1940, issued as U. S. Patent No. 2,322,375, dated June 22, 1943.

This invention relates to an improved process for the production of salts of carbaminoyl choline and carbaminoyl substituted-cholines, having the formula where R1 and R2 may be selected from the group consisting of alkyl radicals and hydrogen, and X is a halogen radical.

Such carbaminoyl choline and carbaminoyl substituted-choline salts are of therapeutic interest because of the efiects which they exhibit upon the blood pressure.

Essentially, the process of our invention comprises treating a choline salt or a substitutedcholine salt, such as an ocor fi-methylcholine salt, with phosgene and ammonia in an inert organic media, and, after appropriate working up, recovering the corresponding carbaminoyl derivative.

The carbaminoyl choline and carbaminoyl substituted-choline salts may be prepared directly from corresponding choline or substituted-choline salts.

Also, salts of acids the silver salts of which are more soluble than silver iodide may be prepared from carbaminoyl choline or carbaminoyl substituted-choline iodides by treating the latter with Example I About 3 gms. of p-methylcholine chloride are stirred at room temperature with an excess of phosgene dissolved in 50 gms. of chloroform, for about two hours. Excess phosgene and hydrochloric acid are removed by distillation under vacuo. Additional chloroform is added to the syrup and the mixture is poured into excess ammonia dissolved in chloroform and cooled in solid carbon dioxide-acetone. The solid is filtered and extracted with hot absolute alcohol. The solid in the alcohol i precipitated with ether, filtered, and recrystallized from isopropanol. The carbaminoyl-p-methylcholine chloride obtained has a melting point of about 220 C.

Example II About 14 gms. of choline chloride are stirred with a solution of about 20 gms, of phosgene in gms. of chloroform for about two hours at room temperature. The mixture becomes a. twophase liquid mixture. Hydrochloric acid and excess phosgene are removed by distillation in vacuo. Chloroform is added to the syrup, and the mixtureis then added to a solution of excess ammonia in chloroform which was cooled with solid carbon dioxide-acetone. The mixture is filtered, and the solid is extracted with hot absolute alcohol. The solid in thealcoholic solution is precipitated with ether, and filtered. It is recrystallized from a methyl alcohol-ether mixture; the carbaminoyl-choline chloride obtained has a melting point of about 2082l0 C.

Example III About 2 gms. of a-methylcholine chloride are stirred with excess phosgene dissolved in chloroform for abouttwo hours at room temperature. Excess phosgene and hydrochloric acid are removed by distillation in vacuo. Chloroform is added to the remaining syrup and the mixture is added to a solution of ammonia in absolute alcohol. The mixture thus obtained is filtered and the solid in the filtrate is precipitated with ether and recrystallized. The carbaminoyl-a-methylcholine chloride obtained has a melting point of about -188" C.

Carbaminoyl-.;3-methylcholine iodide may also be prepared by first preparing carbaminoyl dimethylaminoisopropanol and then reacting the latter with methyl iodide as shown in the following example:

Example IV About 20 gms. of dimethylaminoisopropanol are added to a solution of about 25 gms. of phosgene in about 200 cc. of chloroform with stirring and cooling. Hydrogen chloride and excess phosgene are evaporated ofi. Additional hloroform is added and the mixture is added to a cold solution of ammonia in chloroform. After about two hours, about 100 cc. of water are added and the aqueous solution saturated with potassium carbonate. The mixture is separated, and the aqueous solution extracted with ether. The chloroform and ether mixture is dried with anhydrous potassium carbonate and distilled. The urethane of dimethylaminodiisopropanol is distilled at about 30 mm. pressure and about 139-140" C.

To about 2 gms. of the urethane of dimethylstance selected from the group consisting of dimethylamino-isopropanol and 2-dimethy1aminoc propanol with phosgene in chloroform thereafter reacting with ammonia' in chloroform, and

treating the reaction product with methyl iodide.

2. The process comprising reacting dimethyiaminoisopropanol with phosgene in chloroform. thereafter. reactin with ammonia. in chloroform, and treating the reaction product with methyl iodide.

3. The process comprising reacting- 2-dimethylan'iino propanol with phosgene in chloroform, chloroform, and treating the reaction product I with methyl iodide.

thereafter reacting with ammonia in RANDOLPH T. MAJOR. HOWARD T. BONNE'I'I.

CERTIFICATE OF CORRECTION.

Patent No. 2,57%567. April 21;, 191

RANDOLPH T. MAJOR, ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 1, sec- 0nd column, line 52, Example IV, for "dimethylaminodiisopr'openol read" -dimethylsminoisopropanol-; and that the said Letters Patent should be read with this correction therein that the same may conform to the record or the case in the Patent Office.

Signed and sealed this 21st day of August, A. D. 1911.5.

Leslie Frazer (Seal) First Assistant Commissioner of Patents. 

